Printed Circuit Board Implementation of N-Way Power Combiner With Isolated Input Ports

A planar implementation of N-way radial power combiners with isolated input ports is presented. While keeping the design simple, the presented combiner can be manufactured solely using printed circuit board technology, and as a result, has a low weight and manufacturing cost. As proof of concept, two power combiners are designed and built. First, a 6-way combiner working at the center frequency of 3.1 GHz with a fractional bandwidth of around 30% was designed. Our measurements of the fabricated combiner showed an input and output return loss of better than 10 dB in a frequency band of 2.65-3.55 GHz where an isolation of higher than 23 dB, amplitude balance of ±0.1 dB, and phase balance of ±1 degree between the input ports were obtained. Then, a simple approach was implemented to widen the frequency band, achieving a fractional bandwidth of 80%. According to our measurements, the wideband combiner has an operating frequency band of 1.35-3.15 GHz, in which an input and output return loss of better than 10 dB with an isolation of higher than 21 dB, amplitude balance of ±0.15 dB, and phase balance of ±1 degree were achieved.